The current LMDE 2 has only the MATE blend with the default Cinnamon, there is lacked of the Qt blends, and outside Cinnamon I am also an LXQt lover, and then the MOST LXQt newcomers are Gtk+ refugees, which KDE also integrates Qt alongside Gtk+, so will LMDE 3 begin the LXQt spins, with the fresh stabilized Buster codebase, which I am unsure when will LMDE 3 be out?

A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.- Max Planck

I stand my ‘‘fresh stabilized Buster’’ for the future Buster stabilization in early 2019, but this does NOT need to be related to LXQt.
You may now add the LXQt blend under our Stretch repobase, for our upcoming LMDE 3 as branded-new.